Can you tell me the screen width/height and area UI width/height?
The picture are 48x48 pixel?
yes, they are 48x48.
Ok thanks ! I'll try to reproduce the error.
Just a curiosity, does your pictures have transparencies or is full colour?
Full color 48x48 png
V1.4 is out and SHOULD fix the problem, if not then there could be a plugin conflict
